Centrifugal pump



June 9, 1964 L. BOOD 3,136,258

CENTRIFUGAL PUMP Filed June 1, 1961 INVENTOR. Lowe/s 15002) United States Patent 3,136,258 CENTRIFUGAL PUMP Louris hood, Voorhurg, Netherlands, assignor to Mowid Anstalt, Vaduz, Liechtenstein, a corporation of Liechtenstein Filed June 1, 1961, Ser. No. 114,222 Claims priority, appiication Netherlands June 8, 1960 3 Claims. (Cl. IMF-87) The invention relates to a centrifugal pump, which consists of a motor compartment containing an electric motor in a water-tight stator casing, a sealing chamber comprising an oil-filled reservoir, and a pump compartment fitted with a suction part, a pump fan, and a discharge part.

Pumps of this kind are used in practice for handling sewage and the like. The disadvantage of these pumps is that owing to the presence of the oil reservoir between the pump compartment and the stator easing no sufficient cooling of the electric motor cantake place. These pumps accordingly can only be applied for intensive use in places where the surrounding cooling liquid cannot fall below the motor compartment.

The object of the invention is to obviate this drawback, and this is achieved by the fact that the motor compartment continues beyond the oil reservoir, in consequence of which the end surface of this compartment extends into the pump compartment and is thus cooled by the liquid present in this compartment.

Owing to this direct contact between motor compartment and liquid to be pumped, sufficient cooling of the electric motor takes place.

Another solution, already applied in practice, of the cooling problem of a not entirely submerged centrifugal pump is attained by the provision round the stator casing of a cooling jacket, through which the discharged liquid is first passed before it passes into the discharge pipe. The drawbacks of this construction are: complicated and expensive construction, additional liquid resistance, and risk of clogging of the discharge pipe due to fouling.

The invention will be explained more fully with reference to the single figure of the drawing showing a vertical sectional view of the pump.

The centrifugal pump consists of an electric motor 1, mounted in a motor compartment 2 which is delimited by a stator casing 3, of a driving shaft 4- supported in two bearings 5 and 6, of an oil-filled sealing chamber 7, and of a pump compartment 3, in which have been fitted a pump fan 9 on the shaft 4, an inletopening 10, and a discharge passage 11.

The oil-filled sealing chamber 7 has been sealed by means of a double mechanical seal 12, 13 from the pump compartment 8 and the motor compartment 2. The oil in this sealing chamber serves as a supplementary water seal and as a lubricant and a cooling agent for the double mechanical seal.

3,136,258 Patented June 9, 1954 The motor compartment 2 has been lengthened by means of a compartment 14 beyond the oil-filled chamber 7, the end surface 15 of the compartment 14 being cooled at the lower end by the liquid to be handled, in consequence of which a satisfactory delivery of heat can take place. This contrasts with the conventional construction, in which the oil reservoir fully separates the motor compartment from the pump compartment.

The thermal conductivity of the end surface 15 can be increased even further by filling the motor compartment with a heat-conducting medium. The end surface 15 can also be equipped with one or more cooling ribs.

What I claim is:

1. A pump comprising a water-tight casing defining a motor compartment therein, motor means including a shaft rotatable thereby disposed in said motor compartment, an oil-filled sealing chamber disposed at one end of said water-tight casing'through which said shaft passes, a pump compartment having an inlet opening, said pump compartment being disposed adjacent said oil-filled sealing chamber, a discharge opening disposed from said pump compartment, and a pump fan mounted on said shaft within said pump compartment to draw a fluid therein through said inlet opening and discharge said fluid through said discharge opening, said water tight casing having a lengthened part including end portions surrounding said oil filled sealing chamber and being substantially equidistantly spaced about said shaft whereby a recess is provided adjacent such oil filled sealing chamber between said lengthened part and said shaft, said lengthened part extending substantially within said pump compartment to always be in contact with said fluid being pumped so as to cool said motor compartment, said pump fan being separated from said end portions and said discharge opening being adjacent to said lengthened part whereby said pump fluid is caused to be directed into contact only with said lengthened part.

References Cited in the file of this patent UNITED STATES PATENTS 2,107,481 Johnson Feb. 8, 1938 2,320,708 Yost June 1, 1943 2,369,282 Curtis et al Feb. 13, 1945 2,384,254 Meredew Sept. 4, 1945 2,404,635 Hoover July 23, 1946 2,404,783 Blom July 30, 1946 2,506,827 Goodner May 9, 1950 2,704,516 Mock et a1 Mar. 22, 1955 

1. A PUMP COMPRISING A WATER-TIGHT CASING DEFINING A MOTOR COMPARTMENT THEREIN, MOTOR MEANS INCLUDING A SHAFT ROTATABLE THEREBY DISPOSED IN SAID MOTOR COMPARTMENT, AN OIL-FILLED SEALING CHAMBER DISPOSED AT ONE END OF SAID WATER-TIGHT CASING THROUGH WHICH SAID SHAFT PASSES, A PUMP COMPARTMENT HAVING AN INLET OPENING, SAID PUMP COMPARTMENT BEING DISPOSED ADJACENT SAID OIL-FILLED SEALING CHAMBER, A DISCHARGE OPENING DISPOSED FROM SAID PUMP COMPARTMENT, AND A PUMP FAN MOUNTED ON SAID SHAFT WITHIN SAID PUMP COMPARTMENT TO DRAW A FLUID THEREIN THROUGH SAID INLET OPENING AND DISCHARGE SAID FLUID THROUGH SAID DISCHARGE OPENING, SAID WATER TIGHT CASING HAVING A LENGTHENED PART INCLUDING END PORTIONS SURROUNDING SAID OIL FILLED SEALING CHAMBER AND BEING SUBSTANTIALLY EQUIDISTANTLY 